<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>拖拽</title>
  </head>
  <style>
    .box {
      background: black;
      width: 100px;
      height: 100px;
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate3d(-50%, -50%, 0);
    }
  </style>
  <body>
    请写出 html css js，拖拽鼠标完成选中 box。

    <div class="box"></div>
  </body>
  <script>
    // 写出实现步骤
  </script>
</html>
